#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<unistd.h>
#include<sys/types.h>
#include<sys/wait.h>

void writer(int wfd)
{
    const char * str = "hello father, I am child";
    char buffer[128];
    int cnt = 0;
    pid_t pid = getpid();
    while(1)
    {
        snprintf(buffer,sizeof(buffer),"message: %s ,pid %d,count %d\n",str,pid,cnt);
        write(wfd,buffer,strlen(buffer));

        cnt++;
        sleep(1);
    }
}

void reader(int rfd)
{
   char buffer[1024];
    while(1)
    {
      ssize_t n = read(rfd,buffer,sizeof(buffer)-1);
      printf("father get message:%s\n",buffer);
    }
}

int main()
{
    int pipefd[2];
    int n = pipe(pipefd);
    if(n < 0) return 1;
    printf("pipefd[0]:%d,pipefd[1]:%d\n",pipefd[0],pipefd[1]);//3 //4 /*0号 读， 1 号 写*/

    pid_t id = fork();
    if(id == 0)
    {
        //child
        close(pipefd[0]);

        writer(pipefd[1]);

        exit(0);
    }
    //父
    close(pipefd[1]);   
    
    reader(pipefd[0]);
    wait(NULL);
    return 0;
}
